A Specification for the Design of Steel-Concrete Composite Columns

Subcommittee 20—Composite Columns was designated in 1973 as a standing committee of the Structural Stability Research Council (formerly called the Column Research Council). With an abundant background of experience regarding steel column behavior, the Council recognized that steel-concrete composite compression members should behave almost the same as plain steel columns if, in composite cross sections, the strength and stiffness of the structural steel alone were several times greater than the strength and stiffness of the structural concrete. The Council was also aware that if, in a composite cross section, the strength and stiffness of the concrete alone were significantly greater than the strength and stiffness of structural steel, the composite compression member would behave much the same as an ordinary reinforced concrete column. Design concepts traditionally applied to structural steel involved fundamental differences from those generally applied to reinforced concrete. The consequences of unequal results from the different design concepts required reconciliation within a rational statement of recommended practice for composite column design.